Effects of β-Casomorphin-5 on Passive Avoidance Response in Mice

摘要: The effects of intracerebroventricular (i.c.v.) injection bovine β-casomorphin-5 (β-CM-5: Tyr-Pro-Phe-Pro-Gly), a μ-opioid agonist derived from milk β-casein, on step-down type passive avoidance tasks were investigated in mice. Intracerebroventricular administration high dose (10 μg) β-CM-5 produced significant decrease latency. β-Funaltrexamine (5 μg, i.c.v.) almost completely reversed the β-CM-5-induced shortening latency, although neither naltrindole ng, nor nor-binaltorphimine had any influence effect β-CM-5. Meanwhile, low (0.5 inhibited scopolamine (1 mg/kg)-induced impairment response. These results indicated that induces amnesia, whereas ameliorates scopolamine-induced amnesia.